A larger headquarters gives Diversified Systems Inc. room not only to add staff but form problem-solving "collectives" with the larger IT consulting firms it often subcontracts with, CEO Archie Williamson said. The software and mobile app developer, which does most of its work for federal and state governments, plans to move to Westerville from leased space in Gahanna after buying and renovating a 10,280-square-foot office building at 100 N. Dorchester Square. It landed an $810,000 minority business...